Hark! A new project appears on the horizon! Dungeon Blocks is the latest and greatest 3D printing Kickstarter from Zheng Labs! Give it a look and spread the word! http://www.zheng3.com/2012/05/15/the-penny-catapult/ Here's a basic torsion catapult. It uses one or more elastic bands to launch a U.S. penny if you print it at 1:1 scale. You probably won't get enough torque to be impressive with fewer than 3 bands. Penny not included!